Evaluation of cement soundness using the ASTM C151 autoclave expansion test

In this research, the expansive behavior and microstructure of cements having different MgO contents and autoclave expansions were investigated. Cements were found that failed the ASTM C151 autoclave expansion test (AET) limit while still being well below the chemical MgO limit, while other cement samples from the same source and with similar MgO contents passed the AET expansion limit. While it is desirable to assess cement soundness using an accelerated technique, the test result must reflect the long-term behavior. In the current study, paste, mortar, and concrete prisms were stored at different temperatures and it was found that the AET provides an unrealistic basis for assessing volume stability as well as for rejecting portland cements for use in concrete.